Enphase vs SMA

DDuffeeInc · May 2011

Getting pretty close to installing our first system. I wanted to look at various options here and pick what looks best to us.

We have plenty of room with no shading on our building. At first I thought about using 22 Kyocera 235 watt panels to an SMA inverter. We have 3 phase 208 power so the inverter would be best to match the voltage and phases.

Now I started taking a look at the Enphase inverters for the reason that you can see the monitoring. On our building this will be a selling point to people who walk into our office. This monitoring would be on display right when you walk in.

Also we have plans to install a 2nd system probably the same size on the other side of our building. Again we have no shading on the 2nd side either. So if we use the Enphase on the 1st install we have the option of the same system of going to a different setup with an single inverter system.

The Enphase setup is a little more in costs than the single inverter system.

I am requesting any input from the more experienced people here to speak up and let me know if you have any thoughts or issues. Thanks to everyone.

stephendv · May 2011

Re: Enphase vs SMA

There are a few options for monitoring solutions with the SMA line. There's the simple bluetooth display or direct computer control or using the more expensive webbox solution which will let you upload data to the web and of course view it on a screen wherever you like.

See: http://www.sma-america.com/en_US/products/monitoring-systems

The SMA transformerless inverters are now available in the US (the one's with TL in the name) which are a few percent more efficient than the enphases. As you've said there aren't any shading issues so no advantage for the enphases.

EDIT: Check the price of the SMA webbox when doing comparisons though, it aint cheap!

drees · June 2011

Re: Enphase vs SMA

WOW - the TL series are impressive - you can see CEC test results for a few here:

http://gosolarcalifornia.ca.gov/equipment/inverter_tests/summaries/

The 8000 series is 98% CEC weighted over the 96% of the old one - most impressive at 10-20% loads where efficiency doesn't start dropping off like the old inverters at 300V 10-30% load it's 99% efficient!

If you're looking at Enphase - keep in mind that the new M215 inverters should be available very soon which improve on the M190 or D380 of the current product line.

As to choosing one over the other - it seems like you're pretty well aware of the issues - if you search the forum it's been discussed in depth a couple of times as well.

jcgee88 · June 2011

Re: Enphase vs SMA

stephendv wrote: »

There are a few options for monitoring solutions with the SMA line...

An issue with any monitoring software for a central inverter is
that because the central inverter cannot "see" individual PV
panels, it can only report aggregate performance. Thus, you
can really only present two items to the viewer: current
production in kw and the day's bell-shaped power production
curve in kwh. The latter curve willl change slowly, i.e., you'd
have to wait an hour for it change 10%. In summary, such a
display doesn't give you a lot to look at, and once you have
seen it, there's little reason to come back soon and look again.

The Enphase Enlighten software shows current aggregate
production and the bell curve, too. Additionally, since the
software does have access to individual PV panels, the software
displays individual panels' instantaneous power output. The
entertainment value of that is: more items to take in for
the viewer; data is more dynamic, for example, you can see
the effect off a cloud going by - the benefit is the screen changes
frequently and thus is worth looking at even, say, 10 minutes
later; and you can see the output differences among the panels
attributable to manufacturing variances and/or where they
are installed on your roof. Net net, a display showing individual
panels' production is more educational and more interesting.

stephendv wrote: »

EDIT: Check the price of the SMA webbox when doing comparisons though, it aint cheap!

Stephen, how much do you estimate, both for initial cost and on
going software fee (if any)?

John

solar_dave · June 2011

Re: Enphase vs SMA

I agree that per panel monitoring would be a nice feature, and would allow you to hold the output rating warranty on a per panel basis.

The cost on my pair of PV Powered inverters to add monitoring was extreme, like $400+ per inverter. Then add on the cost of running wiring for the interfaces to get the data into a system just seemed ridiculous. The TED allows a aggregated view on a per second basis, I see the clouds go in real time. It has be great for knowing when the system has had issues, just had one where the system needed an AC off reset.

The other advantage to the TED is I can monitor my load side of the equation as well and get a net aggregated value on a per second, hourly and daily basis. I do wish it had a e-mail interface and ways to trigger alerting to my mobile phone but it does have an API to add that, along with a web interface to DL the data in CSV format from each sensor.

Blackcherry04 · June 2011

Re: Enphase vs SMA

When I did the math with Enphase , it was 6-7% $$ of my monthly total harvest. In my case $70.00 a year. It makes a huge dent in your ROI.

jcgee88 · June 2011

Re: Enphase vs SMA

Dave,

solar_dave wrote: »

The cost on my pair of PV Powered inverters to add monitoring was extreme, like $400+ per inverter. Then add on the cost of running wiring for the interfaces to get the data into a system just seemed ridiculous.

Just to make sure I understand what you are saying...

You looked at one monitoring system, and at $400/inverter,
you deemed it too expensive. You then implemented TED.
Is that accurate?

What is the initial and on-going cost for TED?

solar_dave wrote: »

The TED allows a aggregated view on a per second basis, I see the clouds go in real time.

Strictly speaking, every monitoring system allows you
to see the clouds go by in real time, by showing you the
reduced aggregate output. What I meant is that you can
not only read the reduced output number but also can see
the visual pattern of the reduced output across your array.
For example, when I am downstairs in my basement, and I
look at the PV panels display and I see, say, the western
half of the array dark, then that indicates that it's partly
cloudy out and that a cloud is just passing.

solar_dave wrote: »

The other advantage to the TED is I can monitor my load side of the equation as well...

This normally involves attaching a CT to one or more of your
power lines within the circuit breaker box. Is this what you
did? Enphase's software gives you a nice power generation
display, but it lacks an interface to do/add on power usage
tracking capability.

I have looked at egauge for doing that, but it would cost me
about a year's worth of production to pay for egauge.

John

solar_dave · June 2011

Re: Enphase vs SMA

jcgee88 wrote: »

Dave,

Just to make sure I understand what you are saying...

You looked at one monitoring system, and at $400/inverter,
you deemed it too expensive. You then implemented TED.
Is that accurate?

What is the initial and on-going cost for TED?

Yes the initial cost for TED is about $199 with one MTU/CT sensor. No ongoing cost.
http://www.theenergydetective.com/store

jcgee88 wrote: »

This normally involves attaching a CT to one or more of your
power lines within the circuit breaker box. Is this what you
did? Enphase's software gives you a nice power generation
display, but it lacks an interface to do/add on power usage
tracking capability.

I have looked at egauge for doing that, but it would cost me
about a year's worth of production to pay for egauge.

John

Yes initially installed with 2 MTU/CT, one for house load one for solar production, since added a third for additional building/subpanel load. Will add a fourth for the Volt Charging circuit(s). That max out the current TED 5000. Be aware the setup can be daunting, but I understand it is much better now and they do have phone support.

drees · June 2011

Re: Enphase vs SMA

Blackcherry04 wrote: »

When I did the math with Enphase , it was 6-7% $$ of my monthly total harvest. In my case $70.00 a year. It makes a huge dent in your ROI.

As an Enphase customer, I agree. I'd really like them to cut the price to about $1/module/year even though the cost impact is much lower due to the higher electricity costs in my area.

Frxddy · June 2011

Re: Enphase vs SMA

I am new to this whole solar thing. Every day I am reading and learning. One thing I learned is, even though I have no shadows, I have shadows! Every time a cloud goes by and covers one panel, what happens? With a central inverter, the entire system is effected. With micro inverters only that one is bothered.

In the Enphase Envoy owners manual it describes how to use a cable and laptop computer to get the information if a: you have no internet or b: you don't want to pay the $2 a year per panel.

I am still researching the DGM micro inverter. They seem nice, but, honestly, their 20 year warranty, to be gentle, lacks. The fact is after 14 years with an Enphase if it dies they will give you a new one. After 14 years if a DGM dies, they will give you $44. Read the fine print, do the math. They claim a 20 yr warranty, but after 19 years they will give you $11, IF you pay the shipping!

Best of luck to you. Let us know what you decide.

mike95490 · June 2011

Re: Enphase vs SMA

Frxddy wrote: »

I am new to this whole solar thing. Every day I am reading and learning. One thing I learned is, even though I have no shadows, I have shadows! Every time a cloud goes by and covers one panel, what happens? With a central inverter, the entire system is effected. With micro inverters only that one is bothered.
....

Generally, I've found very few clouds that only cover a portion of my arrays. A cloud moving at 5 mph takes about 90sec to shade the entire array. So, what's the value of 70% of output for 90 seconds ?

likely less than the power needed to enter and post this text.

stephendv · June 2011

Re: Enphase vs SMA

jcgee88 wrote: »

Stephen, how much do you estimate, both for initial cost and on
going software fee (if any)?

You can find prices online, just search for: "SMA webbox online store". Seem to go for about $700. There are no ongoing costs, just a once off.
And that's without the communications module in the inverters themselves, which is usually another $100 per inverter. I think the newer TL inverters may come with bluetooth modules already installed.

Fatawan · June 2011

Re: Enphase vs SMA

Enecsys is also an option now for a microinverter with monitoring of individual panels. They are currently available.

jaggedben · June 2011

Re: Enphase vs SMA

A non-microinverter solution to look at is Tigo. (tigoenergy.com) I have no experience or affiliation with them, but I've seen their stuff at a solar conference. The monitoring output is similar to Enphase.

Power-One has also announced an Aurora microinverter, but I'm not aware if they've released any info about monitoring.

drees · June 2011

Re: Enphase vs SMA

Blackcherry04 wrote: »

When I did the math with Enphase , it was 6-7% $$ of my monthly total harvest. In my case $70.00 a year. It makes a huge dent in your ROI.

I guess this isn't an issue any more now that their monitoring is free.

Enphase Energy Launches Third-Gen Microinverters with 25-Year Warranty

System2 · October 2011

Re: Enphase vs SMA

In addition to that, it seems that Tigo is charging $350 every 5 years for licensing the software. I called their sales folks yesterday and discussed this (and they admitted it is not on their website).

Blackcherry04 · October 2011

Re: Enphase vs SMA

dandan14 wrote: »

In addition to that, it seems that Tigo is charging $350 every 5 years for licensing the software. I called their sales folks yesterday and discussed this (and they admitted it is not on their website).

I'd think about what it really is. $350.00 @ $.10 = 3500 kwh or 700 kwh per year for me given away for their monitoring.

I raised a lot of cane on their forum about the cost, the next week they did away with the charge, not that I had anything to do with it. To me it made good business sense to not have it as a profit center, but a selling attribute.

xiphias · October 2011

Re: Enphase vs SMA

FWIW, just about 12 months in with a 4.7 kW Tigo system. Very happy with it. Stable, robust, efficient. No charge for monitoring. The web interface software continues to improve. They collect a lot of data and it is well-suited to detailed analysis, either with their functionality, or by downloading the data and crunching in real software like matlab.

Enphase vs SMA

Comments

Categories